The invention relates generally to a mounting device for electrically connecting integrated circuits to printed circuit boards. More particularly the invention relates to a double sided multi-layer mounting module for electrically connecting a plurality of surface mount integrated circuits to a printed circuit board.
It is well known in the art to mount integrated circuit packages in electrical connection with one side of a printed circuit board. Typically, the integrated circuit packages are positioned in parallel with the plane of the printed circuit board and hence occupy a relatively large amount of space on the board. As electronic devices become more complex and devices such as mainframe computers and minicomputers employ more integrated circuits, it is desirable, if possible, to avoid increasing the size of the cabinets which hold the electronic systems comprising the computers.
One method of solving this problem has been to employ a system and module for mounting integrated circuit packages in electrical connection with opposite sides of a sheet-like rectangular insulating structure. Typically the structure is comprised of one or more stacked sheets of insulating material, such as polyimide and the like. Electrical connection from the legs of the surface mount integrated circuit packages to the conductive traces on the printed circuit board is effected through electrical connectors mounted on the surfaces of the module which contact the legs of the surface mount integrated circuit packages. The electrical connectors terminate in pads to which are bonded by simultaneous soldering a plurality of legs comprised of a lead frame which extends from the outside surface downward from the module. The legs are adapted to be placed in conductive engagement with a plurality of plated through holes in a printed circuit board having connected thereto the printed circuit board conductive traces.
It may be appreciated, however, that this system, while saving some space, is not as space efficient as it might be. The fact that the lead frame conductors must be attached to the conductive traces on the outside of the modules causes a portion of the module faces to be consumed by such lead frames which cannot be used by surface mount integrated circuit packages. This causes the modules to have a height which extends at least as far above the printed circuit board as the length of the lead frame leads and the width of the surface mount devices attached to the module.
What is needed is a more compact module for connecting a plurality of integrated circuits in substantially perpendicular orientation to a conventional printed circuit board.